Nonstoichiometric Molybdenum Trioxide Adjustable Energy Barrier Enabling Ultralong-Life All-Solid-State Lithium Batteries

The performance of lithium batteries is largely dependent on the ionic conductivity within robust solid electrolytes. Poly(ethylene oxide) (PEO)-based electrolytes, however, have a low lithium ionic conductivity, which limits the hop of Li+. Herein, a novel PEO-based composite electrolyte is prepared that contains nonstoichiometric transition molybdenum trioxide (MoO3-x) nanosheets as fillers to improve the ionic conductivity. The MoO3-x nanosheets containing many oxygen vacancies can cross-link with PEO chains to reduce the energy barrier of Li+ migration and the matrix crystallinity, leading to an increase in the lithium-ion transference number (up to 0.56) and a high ionic conductivity (up to 6 x 10(-4) S cm(-1)) at 60 degrees C. Meanwhile, the incorporation of MoO3-x nanosheets alleviates the decomposition of the electrolyte, enhancing the tensile strength by similar to 4 times compared to PEO. As a result, a LiFePO4/Li cell with PEO/LiTFSI/MoO3-x (PLM3-x) delivers an excellent rate capability, high capacity, and lifespan during high rates (2 C, >= 10 000 cycles), which demonstrates a facile yet effective strategy toward high-performance lithium batteries.

Automated summary

A novel PEO-based composite electrolyte doped with MoO3-x nanosheets as fillers was prepared to enhance the lithium ion conductivity and improve the stability of the electrolyte. Compared to traditional PEO electrolytes, the new composite electrolyte exhibits higher ion conductivity and tensile strength, maintaining excellent performance during high-rate cycling.